System and method for detecting key actuation in a keyboard

ABSTRACT

A system and method for detecting key actuation in a keyboard assembly, which, in one embodiment, is used as a conductor to electrically communicate with an information appliance. The rows in the keyboard assembly are electrically isolated from one another, and each row contains keys bridging a two-wire bus. Each key has a switch that is closed during key actuation, a diode to polarize the key, and a resistor to provide a resistive load when the switch is closed and the diode is biased with the current flow. Alternatively, each key has a switch that is closed during key actuation, a timer with an output that goes high after a predetermined time period, and a resistor that provides an identifying load when the switch is closed and the output of the timer is high. Other features of the invention include a linear matrix coupled to a row of keys to allow the row to be scanned by sections and individual keys, and a flexible circuit that provides the electrical pathways for the linear matrix.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the invention

[0002] The invention relates generally to systems and methods fordetecting key actuation in keyboard assemblies for information devices,and more particularly to systems and methods for detecting key actuationin keyboards for such devices.

[0003] 2. Background information

[0004] Small portable computers or “palmtops” can be convenientlycarried in a purse or coat pocket. Recent advances in shrinking the sizeof electronic components will soon allow these devices to perform allthe functions of today's desktop computers. Additionally, a whole newcategory of “information appliances” has begun. These include portablewireless telephone/computers which can be used to access the Internet tosend and receive e-mail and to interact on the World Wide Web.

[0005] Powerful and versatile as these devices are becoming, their useis greatly limited by non-existent or inadequate keyboards. Palmtopswhich rely on handwriting recognition have proven to be awkward, slowand error prone. Miniature keyboards commensurate with the size of smallappliances are likewise frustrating, especially if the user needs towrite something consisting of a few sentences or more. Voice recognitionsuffers from frequent errors and creates a lack of privacy when otherpeople are near the speaker whose voice is being recognized. Further,voice recognition may not be used in all circumstances (e.g. the processof taking notes of a lecturer's lecture in an otherwise quiet auditoriummay not be possible with voice recognition input systems but it isusually possible with a keyboard).

[0006] Keyboards for desktop and high quality laptop computers allow theuser to comfortably, privately, quietly, and quickly “touch-type.” Theyhave a number of desirable features in common. Most keyboards have astandard “QWERTY” layout which requires no learning on the part of theuser (once the user has become familiar with this layout). The keys,which usually number 84 for a laptop computer, have full-sized topswhose center-to-center spacing is about 19 mm for both the horizontaland vertical axes. The length of the keyboard (the distance from theleft edge of the left-most key to the right edge of the right-most key)is about 11 inches. Any reduction in this spacing has proven to slowdown and frustrate the touch-typist. Additionally, the keys of thesekeyboards have sufficient “travel,” the distance the key moves when itis pressed, and tactile feedback, an over-center buckling action, thatsignals the user that the key has been pressed sufficiently.

[0007] Efforts have been made to provide keyboards that contain thesefeatures, yet collapse to a reduced size. Some designs only slightlyreduce the size of “notebook” computers when folded. These are muchlarger than palmtop computers. IBM's “ThinkPad 701C” notebook computerfolds in a single operation to reduce the keyboard case length (measuredfrom the edges of its case) from 11.5 inches to 9.7 inches. Also seeU.S. Pat. No. 5,543,787 which describes a foldable keyboard. U.S. Pat.No. 5,519,569 describes a keyboard which folds in multiple steps from alength of 10-11 inches to 6.125 inches. U.S. Pat. No. 5,654,872describes a keyboard with keys that collapse when the lid is closed toallow a thinner notebook computer.

[0008] Other designs of keyboards include those where the keyboard ishinged at the center of its length and folds about a vertical axis. U.S.Pat. No. 5,457,453 describes a keyboard that folds to greater than halfits length. U.S. Pat. No. 5,574,481 describes a keyboard that folds inhalf and appears to have a non-standard layout of keys (the keys on thecenter fold axis have edges which lie in a straight line). U.S. Pat. No.5,653,543 describes a keyboard that folds in half. U.S. Pat. No.5,502,460 describes a keyboard with two vertical hinges that folds togreater than half its unfolded length.

[0009] U.S. Pat. Nos. 5,044,798 and 5,141,343 describe keyboards whosekeys have user-selectable variable spacing. These designs havenon-standard layouts (e.g., the “Enter” key is rotated ninety degrees)and no self-containing housing. Their frame is made of telescopingsections that create a good deal of friction and could easily bind.

[0010] Keyboards electrically communicate information to informationappliances. Most keyboards have printed circuit boards or membraneslocated underneath their keys. When a key is pressed it shorts thecircuits in a particular column or row. The matrix of columns and rowsthat make up a keyboard is continually scanned by a controller todetermine which keys have been pressed. Such an arrangement isdescribed, for example, in U.S. Pat. No. 5,070,330. The electronicconfiguration of most keyboards thus necessitates a matrix of conductorsthat limits the collapsing of the keyboard to a certain size.

SUMMARY OF THE INVENTION

[0011] The present invention provides, in one example of the invention,a system and method for detecting key actuation in a keyboard assembly.In one embodiment, the keyboard assembly is a collapsible keyboard whichincludes a support element and a plurality of keys. The support elementcan be extended to provide a structure having a first footprint andcontracted to a structure having a second footprint, where the secondfootprint takes less surface area than the first footprint. Theplurality of keys are coupled to the support element. Each of these keysincludes a key top, which is designed to be pressed by a user, and a keybase which is coupled to the key top. The key top and the key baserotate, in one example of the invention, on a pivot point which couplesthe key base to the support element when the support element is extendedand contracted.

[0012] In one exemplary embodiment, the invention provides detection ofkey actuation for a keyboard assembly that is capable of collapsing intoits own protective housing. The housing consists of two symmetricalhollow box-shaped members, opened on one side. When closed, it forms adust-proof enclosure surrounding a keyboard mechanism. When the keyboardassembly is in its collapsed position or state, it measures about4.0-4.7 inches vertically (depending on the inclusion and height of“function” keys), 3.25 inches horizontally, and 1.25 inches deep. In thecollapsed state, the keyboard assembly can be carried in a purse or coatpocket along with a palmtop computer or other information appliance,such as a cellular phone. Its small size allows it to be convenientlystowed inside an appliance, such as a desktop telephone or television.When used with desktop computers or other information appliances, thecollapsed state may be used to better utilize desk space when thecomputer is not in operation.

[0013] Expanding the keyboard from a collapsed state to a keyboardhaving conventionally spaced keys is done in a single step in oneexample of the invention. The user simply pulls the two halves of theprotective housing apart. The housing remains attached, so it cannot bemisplaced, and so the unit can be enclosed and protected in an instant.The housing may also include a cursor control device or a pointingdevice such as a touch-sensitive trackpad or joystick-like device suchas IBM's TrackPoint (found on IBM's ThinkPad laptop computers). Thiscursor control device is, in one exemplary embodiment, selectivelypositionable on either the left or the right sides of the keyboard.

[0014] In one embodiment of the invention, key actuation detection isprovided for a keyboard assembly having keys coupled to and supported bya support element which is a series of rows of multiple scissors-like,diagonally or X-shaped hinged linkages connected to the assemblyhousing. The linkages are selectively shaped such that any keyboardlayout may be adopted, including the standard ‘QWERTY’ layout with itsstaggered columns and various width keys. The linkages also provide awide ratio of contraction, yet due to their diagonal shape whenexpanded, provide a strong and rigid structure. The hinged linkagescreate very little friction and do not require lubrication, so thekeyboard assembly can be repeatedly opened and closed smoothly andeasily. The keys are pivotally attached to the linkages, and by means ofswing arms, pivot from a near vertical position, when the keyboardassembly is collapsed, to a horizontal position, when the keyboardassembly is expanded. To provide for a more compact profile when theassembly is collapsed, the keys are compressed to a closed and nestingposition.

[0015] In one exemplary embodiment of the invention, the mechanicalstructure of the keyboard assembly is used as a conductor toelectrically communicate with an information appliance. The rows areelectrically insulated from one another, and each row contains keysbridging a two-wire bus. The rows are sequentially scanned by acontroller. In another embodiment, each key has its own transpondercircuit which identifies the particular key. When a key is pressed andthe controller scans the row the key is in, the key's transpondercircuit indicates the identity of the key.

[0016] In another embodiment of the invention, the keys in each row of akeyboard assembly are arranged in two polarity groups by a diode coupledto each key. Each key in a polarity group has a different resistive loadprovided by a coupled resistor. Polarizing the keys allows the highestand lowest resistor values to define a reasonable range. Each keyincludes a key switch which is normally open and is closed when the keyis pressed. When the switch is closed and the diode is biased with thecurrent flow, the resistor will determine the resistive load of thepressed key. The keys in each row are coupled in parallel between twoconductors.

[0017] In another embodiment of the invention, a keyboard assembly hasrows of keys in which the keys in each row bridge two buses. Each keyhas a timer coupled to a switch and an electrical identifier, such as aresistor. The output of each timer goes high after a particular timeperiod. When the switch is closed and the output of the correspondingtimer is high, the electrical identifier provides an identifying load. Asignal is sampled at different times to determine if the signal ischanged by the identifying load. If so, a pressed key will beidentified.

[0018] In yet another embodiment of the invention, a linear electricalmatrix is coupled to a row of keys. The row is electrically separatedinto sections, each of which has its own section pathway for signals.Each key in each section is coupled to a key pathway, which is shared bycorresponding keys in each section. Each row has its own set of sectionand key pathways, making the row appear electrically as if it werearranged in a matrix and allowing the rows to be electrically isolatedfrom one another. In one embodiment, all sections are scannedconcurrently to detect any responses from the keys. If a response signalis detected, the sections are scanned individually to identify the keythat provided the response signal.

[0019] In still another embodiment of the invention, a two layerflexible circuit passes through each key assembly in a row of keys andprovides the electrical pathways for a linear electrical matrix. Theflexible circuit has an upper layer with a contact region disposed overthe contact region of a lower layer. Conductive traces on each layer actas section and key pathways to allow signals to travel along the row ofthe keys. The flexible circuit is guided down between keys of a keyboardassembly, allowing the keyboard assembly to be collapsed more easily.

[0020] In one example of a method according to the invention, a row ofkeys is electrically separated into different sections. The differentsections are then scanned sequentially to detect a key actuation signalthat corresponds to a pressed key. A scan code corresponding to the keyactuation signal is sent to a host computer.

[0021] Additional features and benefits of the invention will becomeapparent from the detailed description, figures, and claims set forthbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention is illustrated by way of example and not byway of limitation in the figures of the following drawings in which likereference numerals refer to similar elements.

[0023]FIG. 1 is a planar top view of an embodiment of the keyboardassembly in its expanded position or state in accordance with theinvention.

[0024]FIG. 2 is a planar top view of an embodiment of the keyboardassembly in its collapsed position or state in accordance with theinvention.

[0025]FIG. 3 is a planar front view of an embodiment of the keyboardassembly in its fully expanded position in accordance with theinvention.

[0026]FIG. 4 is a planar front view of an embodiment of the keyboardassembly in a semi-collapsed position in accordance with the invention.

[0027]FIG. 5 is a planar front view of an embodiment of the keyboardassembly in its fully collapsed position in accordance with theinvention.

[0028]FIG. 6 is a planar front view of three keys in Row I of anembodiment of the keyboard assembly in their expanded position inaccordance with the invention.

[0029]FIG. 7 is a planar front view of the three keys illustrated inFIG. 6 in a semi-collapsed position.

[0030]FIG. 8 is a planar front view of three keys illustrated in FIG. 6in their fully collapsed position.

[0031]FIG. 9 is a planar rear view of three keys in one row illustratedin FIG. 6 in their fully collapsed position.

[0032]FIG. 10 is a planar top view of seven keys in two rows of anembodiment of the keyboard assembly in accordance with the invention.

[0033]FIG. 11 is an embodiment of a key mechanism for a key in its openposition in accordance with the invention.

[0034]FIG. 12 is an embodiment of the key mechanism of the key in FIG.11 in its closed position in accordance with the invention.

[0035]FIG. 13 is a top perspective view of ten keys in three rows of anembodiment of the keyboard assembly in their expanded position inaccordance with the invention.

[0036]FIG. 14 is a planar front view of three keys in Row III of anembodiment of a keyboard assembly in their fully expanded position inaccordance with the invention.

[0037]FIG. 15 is a planar front view of the three keys in Row III ofFIG. 14 in a semi-collapsed position.

[0038]FIG. 16 is a planar front view of the three keys in Row III ofFIG. 14 in their fully collapsed position.

[0039]FIG. 17 is a planar front view of three keys in Row V of anembodiment of a keyboard assembly in their expanded position inaccordance with the invention.

[0040]FIG. 18 is a planar front view of the three keys in Row V of FIG.17 in their collapsed position.

[0041]FIG. 19 is a planar rear view of the three keys of FIG. 17 intheir collapsed position.

[0042]FIG. 20 is a planar rear view of an embodiment of the inventionincluding tilt fingers with three keys in their fully expanded positionin accordance with the invention.

[0043]FIG. 21 is a planar side view of an embodiment of the keyboardassembly of the invention in its expanded position having tilt fingersraising the back side of the assembly in accordance with the invention.

[0044]FIG. 22 is a planar rear view of the three keys of FIG. 20 in asemi-collapsed position.

[0045]FIG. 23 is a planar rear view of the three keys of FIG. 20 intheir fully collapsed position.

[0046]FIG. 24A is a top perspective view of a portion of an embodimentof a keyboard assembly in an expanded or open position in accordancewith the invention.

[0047]FIG. 24B is a top perspective view of the keyboard portion shownin FIG. 24A in a collapsed or closed position in accordance with theinvention.

[0048]FIGS. 25A and 25B are two perspective views of a male strut usedin a keyboard assembly in accordance with the invention.

[0049]FIGS. 26A and 26B are two perspective views of a female strut usedin a keyboard assembly in accordance with the invention.

[0050]FIGS. 27A and 27B are two perspective views of an actuator used ina keyboard assembly in accordance with the invention.

[0051]FIGS. 28A and 28B are two perspective views of a key base used ina keyboard assembly in accordance with the invention.

[0052]FIGS. 29A and 29B are two perspective views of another key baseused in a keyboard assembly in accordance with the invention.

[0053]FIG. 30A is a planar front view of a portion of an embodiment of akeyboard assembly in an expanded position in accordance with theinvention.

[0054]FIG. 30B is a planar front view of the keyboard portion shown inFIG. 30A in a partially collapsed position in accordance with theinvention.

[0055]FIG. 30C is a planar front view of the keyboard portion shown inFIG. 30A in a fully collapsed position in accordance with the invention.

[0056]FIGS. 31A and 31B are two perspective views of a key clip used ina keyboard assembly in accordance with the invention.

[0057]FIG. 32 is a flowchart of a method performed in accordance withthe invention.

[0058]FIG. 33 is a flowchart of another method performed in accordancewith the invention.

[0059]FIG. 34 is a flowchart of yet another method performed inaccordance with the invention.

[0060]FIG. 35 is a top view of an embodiment of the electrical layout offour keys of the keyboard assembly in accordance with the invention.

[0061]FIG. 36 is a schematic circuit diagram of an embodiment of a keyencoder for a key assembly for a keyboard assembly in accordance withthe invention.

[0062]FIG. 37 is a schematic electrical block diagram of a typical rowof keys of a keyboard assembly in accordance with an embodiment of theinvention.

[0063]FIG. 38 is a schematic electrical block diagram of a partial rowof keys of a keyboard assembly in accordance with the invention.

[0064]FIG. 39 is a schematic block diagram of a keyboard array coupledto a host computer through a keyboard interface and a microcontroller inaccordance with an embodiment of the invention.

[0065]FIG. 40 is a schematic circuit diagram of a keyboard interfacecontroller circuit in accordance with an embodiment of the invention.

[0066]FIG. 41 is a schematic block diagram of three rows of keys coupledto a host computer in accordance with an embodiment of the invention.

[0067]FIG. 42A is a schematic circuit diagram of an embodiment of a keycircuit for a key assembly used in a keyboard assembly in accordancewith the invention.

[0068]FIG. 42B is a schematic electrical block diagram of a partial rowof keys of a keyboard assembly in accordance with the invention.

[0069]FIG. 43 is a schematic circuit diagram of a keyboard interfacecontroller circuit used with a keyboard assembly in accordance with theinvention.

[0070]FIG. 44 is a schematic block diagram of a keyboard array coupledto a host computer through a keyboard interface and a microcontroller inaccordance with the invention.

[0071]FIG. 45 is a timing diagram of key signals from a keyboardassembly in accordance with the invention.

[0072]FIG. 46 is a schematic circuit diagram of a linear electricalmatrix coupled to a row of keys of a keyboard assembly in accordancewith the invention.

[0073]FIG. 47 is a schematic block diagram of a keyboard array coupledto a host computer through a keyboard interface and a microcontroller inaccordance with the invention.

[0074]FIG. 48A is a planar top view of a flex circuit layer used in akeyboard assembly in accordance with the invention.

[0075]FIG. 48B is a planar top view of another flex circuit layer usedin a keyboard assembly in accordance with the invention.

[0076]FIG. 48C is a planar top view of a flex circuit with two layersused in a keyboard assembly in accordance with the invention.

[0077]FIG. 48D is an example of another embodiment of an array of keysin accordance with the invention.

[0078]FIG. 48E is an example of a keyboard array which includes a cursorcontrol device (e.g. a trackpad) that is selectively positionable oneither side of the keyboard.

[0079]FIG. 49 is a flowchart of a method performed in accordance withthe invention.

[0080]FIG. 50 is a flowchart of another method performed in accordancewith the invention.

[0081]FIG. 51 is a flowchart of yet another method performed inaccordance with the invention.

[0082]FIG. 52 is a flowchart of still another method performed inaccordance with the invention.

[0083]FIG. 53 is a diagram of a digital processing system, such as apersonal digital assistant which is substantially contained in acollapsible keyboard assembly according to one embodiment of theinvention.

DETAILED DESCRIPTION

[0084] The invention relates to detecting key actuation in a keyboardassembly. Specific details of an embodiment of the keyboard assembly aredescribed below. Numerous specific details including keyboard layouts,specific structural arrangements and relationships, etc. are presentedin order to provide a thorough understanding of the invention. It is tobe appreciated that these specific details need not be specificallyemployed to practice the invention and that there are other details thatare not presented so as not to unnecessarily obscure the description ofthe invention that may be substituted or included that fall within thescope of the claimed invention.

[0085]FIG. 1 shows a planar top view of an embodiment of the keyboardassembly of the invention. For convention, the rows of keys are numberedI through VI, with Row I being closest to the user or the front of thekeyboard assembly. Row I includes the “Ctrl” key and row VI includes the“Pause” key. The “front” side of a key is closest to a user situatedclosest to Row I, while the “back” side of the key is farthest from theuser. A vertical distance is measured from the front of the keyboardassembly, closest to the user, to the back of the keyboard assembly,farthest from the user. A horizontal distance is measured from the left(or one side) of the keyboard assembly to the right (or other side) ofthe assembly.

[0086]FIG. 2 shows a planar top view of keyboard assembly 10 of FIG. 1in its collapsed state. For illustration purposes, in FIG. 2, the topportion of each of protective housing sides 1 and 2 is transparent so asto reveal the collapsed state of keys 3. FIGS. 3-5 illustrate a planarfront view of an embodiment of keyboard assembly 10 and show thecollapsible nature of keyboard assembly 10.

[0087]FIGS. 1 and 3 show a top and a front view, respectively, of anembodiment of keyboard assembly 10 in its expanded position. In FIG. 1,it can be seen that the layout of keys 3 of the keyboard assembly 10 isthe same as the standard keyboard. In this embodiment, spacing betweenkeys 3 is full pitch (about 19 mm) in both horizontal and verticaldirections. It is to be appreciated that the invention is not limited tothe keyboard layout presented and that other layouts may be substitutedwithout departing from the scope of the invention. For example, thekeyboard may be a numeric keypad or a set of keys providingpreprogrammed functions. As can be seen from FIG. 3, a row ofinterconnected scissors linkages 4 is coupled at each of both ends ofthe row to a housing. The row of linkages 4 supports a row of keys. Eachkey includes a key top 11 a and a key base 11 b. For each key, the keytop 11 a is coupled to the corresponding key base 11 b. Typically, thecoupling is by some mechanism which imparts a spring action to the keytop relative to the key base such that the key top resists being pressedtoward the key base when the key top is pressed during typing. Pressingthe key top toward the key base usually causes an electrical connectionto be changed; usually this occurs by a switch on the key base beingclosed when the key top is pressed far enough toward the key base,although other implementations may not require a switch.

[0088] As shown in FIG. 3, the row of scissors linkages 4 includes aplurality of scissors linkages which are connected in series. Three suchscissors linkages 4 a, 4 b, and 4 c are shown in FIG. 3 and areconnected from left to right respectively. Each scissors linkageincludes two legs which are coupled together at a pivot point by a pinor rivet. Each scissors linkage is coupled to the next scissors linkagein the row by a pivot point on one leg and a pivot point on another leg.Further details regarding the scissors linkages of one embodiment of theinvention are described below.

[0089] When not in use, keyboard assembly 10 may be kept in itscollapsed position or state by a protective housing composed of sides 1and 2. FIGS. 2 and 5 illustrate planar top and front views,respectively, of keyboard assembly 10 in its collapsed position withprotective housing sides 1 and 2 covering collapsed keys 3. To open thekeyboard for operation, the user holds left and right sides 1 and 2,respectively, and pulls linearly sides 1 and 2 apart. FIG. 4 shows afront view of keyboard assembly 10 in a partially expanded orsemi-collapsed position or state. The user continues to pull apart sides1 and 2 until the keyboard assembly stops expanding (FIGS. 1 and 3).

[0090] The keyboard assembly stops expanding, in one embodiment, whenthe two end legs on each side of a row of scissors linkages arerestricted from closing down upon each other. This can be seen from FIG.3 which shows that a row of scissors linkages 4 is coupled on each sideof the row to a pivot point within the respective housing. Specifically,the housing 2 on the right side of the keyboard assembly is coupled tothe row of scissors linkage at pivot points 24 and 23. This pivot point23 includes an opening in a leg of the last scissors linkage on theright side of the row, and a pin or rivet which extends through theopening and which is attached to the inner wall of the housing 2. Pivotpoint 24 includes an opening in the other leg of the last scissorslinkage on the right side of the row and a pin or rivet which extendsthrough the opening and which pin or rivet also rides in a channel 25formed in the inner wall of the housing 2. The channel 25 allows the pinat pivot point 24 to ride up and down the channel as the keyboardassembly is collapsed and extended respectively. Note from FIG. 4 howthe pivot point 24 has moved to half-way along the channel 25 when thekeyboard is semi-collapsed. The bottom end of the channel 25 defines thestopping point for the extension of the keyboard assembly. A similararrangement exists at the last scissors linkage on the left side of thisrow of scissors linkages as shown in FIGS. 3, 4 and 5. A keyboard on/offswitch at the end of the channel 25 may be activated by a pivot point 24when that pivot point reaches the end of the channel at the end of thekeyboard's expansion. In this way, the end of the keyboard's expansionmay be automatically sensed and power to the keyboard may beautomatically supplied at this point. Each row of scissors linkages istypically coupled in a similar fashion to the inside of housings 1 and2.

[0091] In one embodiment, the full extension of sides 1 and 2 turns onthe keyboard's power, via a limit switch, for example. In anotherembodiment, the full extension of sides 1 and 2 tilts the keyboard byraising the rear side. Once fully expanded, the assembly 10 cancommunicate directly with a computer or other host device via anelectric or electronic link. Examples of contemplated linkages include,but are not limited to, an infrared or radio frequency link, or a cable.

[0092] When not in operation, keyboard assembly 10 may be placed in itscollapsed position (FIGS. 2 and 5) by pushing protective housing sides 1and 2 together until the sides cover keys 3. A latch may determine theend point and the side portions may lock, for example, via a key lockswitch, to provide a measure of security. To provide the most compactfolded size while allowing one-step expanding and collapsing, in oneembodiment, keys 3 are pivotally linked to each other by a row ofscissors-like X-shaped linkages 4. FIGS. 3-5 show the collapsible andexpandable nature of linkages 4.

[0093]FIG. 6 shows a magnified view of three keys 3 of keyboard assembly10 coupled to a row of scissors or X-shaped units or linkages 4. Asshown in FIG. 6, each scissors linkage is composed of two legs pivotallyjoined at hub 5, for example, by flanged pins or rivets 30. Eachscissors or X-shaped linkage is pivotally joined to a horizontallyadjacent scissors linkage at lower and upper hubs 6 and 7, respectively.

[0094] As shown in FIG. 6, three scissors linkages 4 a, 4 b, and 4 c areinterconnected in series along a row. Three keys are supported by thisrow. Each key 3 is supported by and coupled to two adjoining scissorslinkages. Scissors linkage 4 a is comprised of legs 4 d and 4 e whichare pivotally coupled at hub 5 (which is also referred to as a scissorspivot point) formed by overlapping openings in legs 4 d and 4 e. Thescissors linkage 4 a also includes an arm 8 which is rotationallycoupled to hub 6 (which is also referred to as a coupling pivot point)at one end of arm 8 and is rotationally coupled to hub 9 on the key base11 b of the left-most key of FIG. 6. Hub 6 is formed by overlappingopenings in arm 8, leg 4 e and leg 4 f. Hub 9 is formed by overlappingopenings in arm 8 and key base 11 b. Each of these hubs is secured by apin in one embodiment. Leg 4 d of scissors linkage 4 a is rotationallycoupled to leg 4 g at coupling pivot point 7; coupling pivot point 7 isalso rotationally coupled to the key base 11 b of this left-most key.Coupling pivot point 7 is formed by overlapping openings in leg 4 d, leg4 g and key base 11. Coupling pivot point 7 is secured by a pin in oneembodiment of the invention. Leg 4 e of scissors linkage 4 a isrotationally coupled to leg 4 f at the coupling pivot point 6. Legs 4 fand 4 g form the scissors linkage 4 b and are also rotationally coupledtogether by a scissors pivot point 5. Scissors linkage 4 b includes anarm 8 which is rotationally coupled at coupling pivot point 6 to leg 4 gand to leg 4 h of scissors linkage 4 c. The arm 8 of scissors linkage 4b is rotationally coupled to a key base 11 b of the middle key of FIG.6, and this key base is rotationally coupled to leg 4 f of scissorslinkage 4 b and to leg 4 i of scissors linkage 4 c. The leg 4 h and theleg 4 i form scissors linkage 4 c which is rotationally coupled to thekey base 11 b of the right-most key of FIG. 6. The legs 4 h and 4 i arepivotally coupled at the scissors pivot point 5. The key base 11 b ofthis right-most key is coupled to an arm 8 which extends from a couplingpivot point with leg 4 i and is coupled to leg 4 h at a coupling pivotpoint on this key base 11 b.

[0095] FIGS. 7-9 illustrate the pivoting of a row of linkages 4 withrespect to the three keys 3 of FIG. 6. Keys 3 rotate from a horizontalposition (FIG. 6) when keyboard assembly 10 is fully expanded, toapproximately a 45° angle when keyboard assembly 10 is partiallycollapsed (FIG. 7), to a nearly vertical position (FIGS. 8-9) whenkeyboard assembly 10 is fully collapsed. FIG. 9 is a rear view of thecollapsed portion of keyboard assembly 10 of FIG. 8. Arms 8 pivotallyconnect linkage hubs 6 to hubs 9 of keys 3. When expanded, arms 8 andthe row of scissors linkages 4 provide a strong, rigid truss, and theangles assumed by arms 8 and the row of-scissors linkages 4 are suchthat keys are prevented from rotating even if they are pressed hard bythe user.

[0096] As keyboard assembly 10 is collapsed (FIG. 7), hubs 6 and 7,respectively, increase in distance from each other. This causes arm 8 torotate key 3 via hub 9 from its horizontal position toward a verticalposition (in this case in a counterclockwise direction). Effectively,arm 8 pulls down the key 3 in a counterclockwise direction. Whenkeyboard assembly 10 is fully collapsed (FIGS. 8-9), the row of linkages4, arms 8, and keys 3 are, respectively, substantially parallel and, inone embodiment, in contact with one another. While FIG. 9 shows thatthere is some space between a key top of one key and a key base on theadjacent key, there may in certain embodiments be little or no spacebetween a key top on one key and a key base on an adjacent key.

[0097] In the embodiment described, bottom hubs 6, which pivotally jointhe X-linkages 4 and arms 8 at their base, are approximatelyhorizontally equally spaced. When keyboard assembly 10 is fullycollapsed, hubs 6 are in close horizontal proximity to one another. Thiscan be seen from FIG. 5.

[0098] In one embodiment, each row of keys 3 of keyboard assembly 10 ispivotally joined to its adjacent row to provide a strong and stablestructure when keyboard assembly 10 is in an expanded position. FIG. 10shows a planar top view of a portion of keyboard assembly 10. FIG. 10shows a portion of keys 3 from Row IV pivotally coupled to keys 3 of RowV. Three rows of scissors linkages 4 hold these seven keys. Flanged pins29 extend through linkage hubs 7 on each row of scissors linkages andfasten to keys 3 to pivotally secure the top portion of keyboardassembly 10. Each of these pins 29 also pivotally secure at a hub 7 oneleg from one scissors linkage to a leg from an adjacent scissors linkageas shown in FIG. 6. Each row of scissors linkages 4 of FIG. 10 fastens,through these pins 29, to one side of each key along a row of keysthrough the corresponding hub 7. The other side of each key along thisrow is secured to an adjacent row of scissors linkages 4 through themating of another set of pins 29 in the corresponding hubs 7 on thisother side of each key. Flanged rods 31 (shown in FIG. 13) pass throughbottom hubs 6 on each of the three rows of scissors linkages and spacingsleeves 32 to pivotally secure the bottom portion of keyboard assembly10. Each pivot point at the connection between an arm 8 and a key base11 b at a hub 9 is secured by a flanged pin 9 a which extends throughthe opening in the arm 8 and into an opening in the key base 11 b. Asnoted above, flanged pins or rivets 30 are used to secure each scissorspivot point 5.

[0099]FIGS. 11 and 12 show a planar front view of an embodiment of a key3 of keyboard assembly 10. In FIGS. 11 and 12, key 3 is composed of keybase 11 b that is coupled to key top 11 a by a conventional linkagehaving butterfly elements 12 and 48. This linkage allows key 3 to becompressed to a very thin dimension (FIG. 12), yet have a large amountof travel (the distance between its open and closed position). Whenkeyboard assembly 10 is fully collapsed, adjacent keys 3 exert pressureon each other causing them to be maintained in their closed position. Itwill be appreciated that there are numerous alternative types oflinkages which may be used to link between each key top and key base.

[0100] Coupled to the base of key top 11 a of each key 3 is a spring 49that has the shape of a bowl or truncated cone and is made, for example,of an elastomer or elastomer-like material. To type, a user presses onthe key top and compresses the spring 49 as the key top is pushed towardthe key base 11 b. When the compression of spring 49 exceeds apredetermined amount, spring 49 buckles to give tactile feedback to theuser. FIG. 12 shows one example of the buckling of spring 49. Theelastomeric nature of spring 49 also allows it to remain in a compressedposition (when keyboard assembly 10 is collapsed) without fatigue.

[0101]FIGS. 11 and 12 show an example of a key assembly with a flexibleconductor assembly disposed on a key base. In this particular example, aflexible conductor assembly for each row of keys is weaved through keybases of the keys along the row; FIGS. 30A-30C show how this flexibleconductor assembly allows the key assemblies to rotate between anexpanded and a contracted state. A flexible conductor assembly willtypically include a plurality of flexible conductors disposed on or in aflexible film. The flexible conductor assembly may include one or two orthree or more layers of flexible conductors. The flexible conductorassembly bends as the keys of a row are collapsed and bends as the keysare expanded. Each row of keys has its own flexible conductor assemblywhich in one case is a set of 8 conductors in two layers of conductorsrunning along each row. One layer of conductors may represent “columnlines” and another layer of conductors may represent “row lines.” FIG.46 shows an example of “row lines” 801-804, each of which defines aseparate section of a mechanical row of keys and column lines 805-808,each of which is a “column” conductor that is coupled to a particularkey switch. The rows are electrically insulated from each other. FIGS.11 and 12 show an example of a three-layer flexible conductor assemblyin which the row conductor 801 is disposed above (and separated from) acolumn conductor 805 when the key top 11 a is not pressed down againstkey base 11 b. This three-layer flexible conductor assembly includes twolayers of conductive material and one layer of insulating material. Whenthe key top 11 a is pressed down against key base 11 b, the standoff 45a depresses the flexible film 45 b and the row conductor 801 toward thecolumn conductor 805, which causes the column conductor 805 on theflexible film 45 c to electrically contact the row conductor 801 asshown in FIG. 12, thereby closing the switch at this key between thesetwo conductors. It is assumed that in this case the electrical matrix ofFIG. 46 is being used with the embodiment of FIGS. 11 and 12. Theflexible films 45 b and 45 c are separated from each other by aninsulating layer 45 d which includes an opening allowing exposedconductive regions of row conductor 801 and column conductor 805 to makeelectrical contact. While FIGS. 11 and 12 show 2 layers of conductors inthe flexible conductor assembly, it will be appreciated that alternativeembodiments may use any number of layers of conductors. FIGS. 11 and 12show that the key top 11 a and key base 11 b are formed from differentstructures which are joined together. It will be appreciated that, in analternative embodiment, the key base and key top may be made from acollapsible unitary structure.

[0102] As can be seen in FIG. 1, the standard key layout of computerkeyboards has columns of keys which are mostly staggered, rather than instraight columns. Additionally, some keys, for example, the “Backspace”and “Enter” keys (FIGS. 1C and 5) are considerably wider than, forexample, a letter key.

[0103] In order to allow the keyboard assembly of the invention to becollapsed to a minimum length and thickness, the particular embodimentdepicted in the figures utilizes various configurations of linkageshapes, arm lengths, and hub locations on the keys. Additionally, theassembly is configured so that keys rotate in different directions indifferent rows. FIG. 13 illustrates a perspective top view of a portionof keyboard assembly 10 of the invention. Note that there are threedifferent key top sizes. FIG. 13 shows a portion of three rows of keys 3(Rows III, IV, and V) and illustrates the support mechanism of such keysin part by ghost lines to indicate the construction of the mechanismbeneath the keys. Keys 3 are shown in an expanded (opened) position. InFIG. 13, hubs 6 lie in vertical columns and are equally spaced in allrows. Keys 3 in Row III are pivotally supported by the configuration ofa series of X-linkages 4, arms 8, and key hub locations shown in detailin FIGS. 14 and 15. As Row III collapses, keys 3 rotate in a clockwisedirection. The keys in Row IV are pivotally supported by theconfiguration shown in FIGS. 6-9. As Row IV collapses, keys 3 in row IVrotate in a counter-clockwise direction. This allows, in one embodiment,a full-sized laptop keyboard (about 11 inches long excluding its frame)to fold to 3.25 inches in length, including its housing.

[0104] Row III contains the wide “Enter” key 37 which spans two bottomhubs 6. FIGS. 14-16 illustrate a planar front view of the rotation ofthe keys of Row III shown in FIG. 13. To allow the keyboard assembly tofold to a minimum length and thickness, linkage 13 b, located betweenRows III and IV, pivotally supports the front side of the “I\” key inRow IV at hub 14 b, and has an angled extension 15 to pivotally supportthe back side of the “Pg Dn” key in Row III at hub 16. Similarly,linkage 17, located between Row IV and Row V, pivotally supports theback side of the “I\” key at hub 18, and has an angled extension 19, topivotally support the front side of the “Home” key in Row V at hub 20.Linkage 13 shown in FIG. 13 includes a hub 14 a which couples thelinkage 13 to an adjacent leg on the scissors linkage to the right ofthe “Enter” key. The extension 15 of linkage 13 pivotally supports thefront of the “Pg Dn” key at hub 16. This is also shown in FIG. 15. Thehub 7 a is not coupled to the “Pg Dn” key but is coupled to the adjacentscissors linkage to the right of the “Pg Dn” key.

[0105] FIGS. 14-16 show the wide “Enter” key 37 with normal width keyson either side of the “Enter” key. No key in row 3 is attached at hub 14a which allows “Enter” key 37 to rotate unobstructed, but the “I\” keyis attached to hub 14 b. FIG. 16 illustrates that when keyboard assembly10 is in its collapsed position, the vertical distance between hubs 6and 14 is sufficient to accommodate “Enter” key 37 without the keyextending below the bottom 38 of the series of linkages 4. FIG. 16 alsoillustrates that the wide keys and linkage extensions do not add to thehorizontal length of the folded keyboard assembly. The other wide keysof keyboard assembly 10 and their associated linkages and hubs aredesigned similarly, such that the folded depth of the keyboard is keptto a minimum.

[0106] In addition to accommodating keys of different widths, thelinkage design of the invention allows keys on one row to behorizontally displaced with respect to keys on an adjacent row (e.g.staggered key columns), thereby conforming to standard keyboard layouts,such as for example a “QWERTY” layout even though the rows are pivotallyjoined to each other. For example, keys 3 in Row IV are pivotallysupported on the front side by hubs 7 of linkages 4 (FIGS. 6, 10, and13). However, linkages 33 located between Row IV and Row V have angledextensions 21. This is illustrated in FIG. 13 and in a front viewportion of Row V shown in FIG. 17 in an expanded position and FIGS.18-19 in a collapsed position. As shown in FIGS. 13 and 17-19, there aretwo hubs 34 and 35 on extensions 21, which lie on a horizontal axis whenthe keyboard is expanded (FIGS. 13 and 17). In FIG. 13, linkage 33pivotally supports the “{[” key of Row IV at hub 34. The same linkage 33pivotally supports the “+=” key 3 of Row V at adjacent hub 35. In thismanner, the keys in Row V are displaced horizontally with respect to thekeys in Row IV. When fully collapsed, extensions 21 “nest” allowing thelinkages to be compressed to their most compact position. This isillustrated in front and rear views by FIGS. 18 and 19, respectively.

[0107] As shown in FIG. 13, hubs 34 lie along the same vertical axis ashubs 7 which lie along the same vertical axis as rod 31. The X-shapedlinkages 4 and 33, respectively, and their respective extensions havecenters of intersections 5 which lie on a common vertical axis 36 forall rows, even though the keys of different rows are horizontallystaggered and are of different widths. This arrangement allows all rowsto expand and collapse together.

[0108] While the keys in adjacent rows are horizontally staggered, theleft and right terminations of the linkages in all rows lie inapproximately vertical lines. Linkages supporting the left-most keys ofeach row (FIGS. 1 and 3) are aligned horizontally at their bottom hubs 6and their top hubs 22. Similarly, linkages supporting the right-mostcolumn of keys (FIGS. 1, 3, and 13) are aligned horizontally at theirbottom hubs 6 and their top hubs 22. This allows a compact arrangementfor a housing composed of protective housing sides 1 and 2.

[0109] The left and right-most linkages of the embodiment of thekeyboard assembly of the invention are pivotally joined to the housingside portions 1 and 2, respectively, by bottom pivot pins 23 at bottomhubs 6 and slidably joined to the housing side portions 1 and 2,respectively, by top pins 24, which slide in slots 25 of housing sideportions 1 and 2, respectively (see FIGS. 3, 4, and 5). Two sets ofscissors or X-shaped linkages (without associated keys), located on theleft- and right-most sides of keyboard assembly 10, allow the unit to beexpanded so that housing side portions 1 and 2, respectively, are clearof keys 3. In this manner, keyboard assembly 10 can be opened and closedin a one-step operation and does not need to be removed from itsprotective housing. In one embodiment of the invention, the surface ofone of housing sides 1 and 2 may include a cursor control device such asa small trackball, a touch-sensitive trackpad, a joystick, apressure-sensitive pointing device (e.g. IBM's TrackPoint III which isused on IBM's ThinkPad laptop computers), or other cursor control (e.g.pointing) devices. In addition, small buttons may be included on thesurface of the housing; these small buttons may perform the samefunctions as the buttons (or button) on a mouse which is often used witha computer. In another embodiment, the cursor control device isselectively positionable on either one of housing sides 1 and 2.

[0110] FIGS. 20-23 illustrate an additional feature of one aspect of anembodiment of a keyboard assembly of the invention. FIGS. 20, 22, and 23show front view portions of three keys in a row of keyboard assembly 10.FIG. 21 shows a vertical side view portion of keyboard assembly 10. Eachof FIGS. 20-23 illustrate an embodiment of a tilting device that raisesthe rear of keyboard assembly 10 for a comfortable angle similar to thatof desktop keyboards. FIG. 20 shows tilt fingers 26 extended whenkeyboard assembly 10 is in its fully expanded position and FIG. 23 showstilt fingers 26 retracted when keyboard assembly 10 is closed. In FIG.21, keyboard assembly 10 rests on a flat surface at the bottom tips offingers 26 and the front edge of left housing 1 and right housing 2.Thus, the rear of keyboard assembly 10 is elevated to provide acomfortable angle for typing as shown in FIGS. 20 and 21. Each finger 26is pivotally attached to the linkages 4 at hub 7 by a pin at this hub atthe back side of keyboard assembly 10. Flanged pin 27 passes through hub6. FIG. 22 shows the keyboard in a partially collapsed state. Askeyboard assembly 10 is collapsed (FIG. 22), pin 27 slides in slot 28,until collapse is completed (FIG. 23).

[0111]FIG. 24A shows a portion of one embodiment of a collapsiblekeyboard in an expanded position. Each row of keys 200 a-200 d has keysthat are formed by a key top coupled to a key base. Rows 200 a and 200 dhave keys formed by a key top 201 coupled to a key base 202 a. Rows 200b and 200 c have keys formed by key top 201 coupled to a key base 202 b.In one embodiment, the key tops are supported by the key bases throughconventional butterfly linkages (not shown) which allow the key tops tobe pressed down. An interconnected series of male struts 203 rotatablycoupled to female struts 204 in an X pattern connects adjacent rows. Forexample, key base 202 a in row 200 a is rotatably coupled to key base202 b in row 200 b by female strut 204 and a male strut in an adjacent Xpattern. Actuators 205 to facilitate key rotation are shown rotatablycoupled to male struts 203, to a female strut in an adjacent X pattern,and to key bases 202 b in rows 200 b and 200 c. Actuators 205 operate ina similar manner as arms 8, as described with reference to FIGS. 7-9. Inone embodiment, male struts 203, female struts 204, actuators 205, andkey bases 202 a and 202 b snap together for easier assembly. Althoughthe same key top 201 is shown for each key, it is appreciated that keytops of different sizes can be used. The male and female struts,actuator, and key bases are discussed in more detail below.

[0112]FIG. 24B shows the keyboard portion of FIG. 24A in a collapsedposition. The keys in rows 200 a and 200 c have rotatedcounter-clockwise, while the keys in rows 200 b and 200 d have rotatedclockwise. Male struts 203 remain substantially parallel with oneanother, as do female struts 204, but the space between adjacent malestruts 203 and between adjacent female struts 204 is decreased to givethe collapsed position a thin profile.

[0113]FIGS. 25A and 25B show two different views of a male strut or leg250. The male strut 250 may be used as the male strut of FIGS. 24A and24B. Main body 254 has protrusions 252 a, 252 b and 253 a, 253 bextending orthogonally from both ends of main body 254. Protrusions 252a and 253 a are longer than protrusions 252 b and 253 b, respectively. Aprotrusion 251 extends orthogonally from approximately the middle of oneside of main body 254. In one embodiment, protrusions 251, 252 a, 252 b,253 a, 253 b are ridged to provide the snap-together feature mentionedabove. The flange or ridge at the end of these protrusions has adiameter which is slightly larger than the corresponding through hole inthe female strut which is designed to engage the protrusion. Once aprotrusion is snapped into its corresponding hole, the ridge retains themale and female struts. Extension stops 255 a and 255 b extend fromgrooves 256 a and 256 b, respectively, around protrusion 251. Extensionstops 255 a and 255 b limit keyboard expansion by stopping the rotationof a coupled female strut. In another embodiment, male strut 250 issymmetric about an axis perpendicular to the length of male strut 250,where the axis passes through the center of male strut 250.

[0114]FIGS. 26A and 26B show two different views of a female strut orleg 260 that, in one embodiment, is coupled to male strut 250. Thefemale strut 260 may be used as the female strut of FIGS. 24A and 24B.Main body 264 has end through holes 262 and 263 for mating with theprotrusions of male struts in neighboring male-female X linkages when aninterconnected series of X linkages is formed. A middle through hole 261accepts protrusion 251 when male strut 250 and female strut 260 arecoupled together to form an X linkage. Male strut 250 and female strut260 are thus complementary. Extension stops 265 a and 265 b extendingfrom grooves 266 a and 266 b, respectively, around middle through hole261 impinge upon extension stops 255 b and 255 a of male strut 250 askeyboard expansion occurs. In one embodiment, female strut 260 issymmetric about an axis perpendicular to the length of female strut 260,where the axis passes through the center of female strut 260.

[0115]FIGS. 27A and 27B show two-different views of an actuator 270.Actuator 270 has arms 274 a and 274 b. Arm 274 a has grooves 272 a and272 b. Arm 274 b has grooves 273 a and 273 b. Grooves 272 a and 273 amate with protrusions on a key base, and grooves 272 b and 273 b matewith one of protrusions 252 b and 253 b on male struts 250 in adjacentrows, depending on the orientation of male struts 250.

[0116]FIGS. 28A and 28B show top and bottom views, respectively, of akey base 280. Flanges 284 a and 284 b extend out, above and below fromopposite sides of base member 281. Protrusion 282 a extends out from oneend of flange 284 a, and groove 283 a reaches partially through flange284 a. Similarly, protrusion 282 b extends out from one end of flange284 b, and groove 283 b reaches partially through flange 284 b.Protrusions 282 a and 282 b mate with grooves 273 a and 272 a,respectively, of actuator 270. In one embodiment, protrusions 282 a and282 b are ridged to provide a snap-together assembly with actuator 270.Grooves 283 a and 283 b accept one of protrusions 252 b and 253 b ofmale strut 250, depending on the orientation of male strut 250. In oneembodiment, key base 280 is coupled to key top 201 to form the keys inrows 200 b and 200 c. FIGS. 11 and 12 show one example of a way tocouple a key top to a key base using a conventional butterfly linkage.

[0117]FIGS. 29A and 29B show top and bottom views, respectively, of akey base 290. Key base 290 differs from key base 280 primarily in theposition of the protrusion 292 a and protrusion 292 b; these differentpositions allow for different pivot points for the different keys andallow a collapsible keyboard to have different size keys and stillcollapse. Flanges 294 a and 294 b extend out, above and below fromopposite sides of base member 291. Protrusion 292 a extends out fromapproximately the middle of flange 294 a, and groove 293 a reachespartially through flange 294 a. Similarly protrusion 292 b extends outfrom approximately the middle of flange 294 b, and groove 293 b reachespartially through flange 294 b. Protrusions 292 a and 292 b mate withthrough holes in a female strut or in some cases a groove in anactuator. Grooves 293 a and 293 b accept one of protrusions 252 a and253 a of male strut 250, depending on the orientation of male strut 250.It should be noted that either of protrusions 252 a and 253 a of malestrut 250 is long enough to mate with both an end through hole 262, 263of female strut 260 and a groove 293 a, 293 b. In one embodiment, keybase 290 is coupled to key top 201 to form the keys in rows 200 a and200 d.

[0118] FIGS. 30A-30C show a side view of a portion of a row of keys inone embodiment of a collapsible keyboard as the keyboard is collapsed. Akey clip 302 is disposed between a key top 301 and a key base 304.Although it is not shown for purposes of clarity, in one embodiment, abutterfly linkage couples key top 301 to key clip 302. Key clip 302holds a flex circuit 303 (e.g. a flexible bus of conductors) flatagainst key base 304 by snapping onto key base 304 with flex circuit 303in between. A hook 305 at one end of key clip 302 guides flex circuit303 down between adjacent keys, thereby allowing the keyboard tocollapse more easily to a compact, closed position. The clip 302relieves stress in the portions of the flexible circuit 303 which bendby keeping one portion fixed (around the edge of the key base) andanother portion loose (with a wide angle for bending).

[0119]FIGS. 31A and 31B show top and bottom views, respectively, of akey clip 310. Tabs 312 a-312 d snap key clip 310 onto a key base (notshown) as key clip 310 is pressed against the key base. In one exemplaryembodiment, a flex circuit is laid on top of the key base before the keyclip is snapped into place onto the key base. Once key clip 310 issnapped onto the key base, a flex circuit (not shown) located betweenkey clip 310 and the key base is held flat against the key base. Guidearms 315 a and 315 b are curved downward to force the flex circuit downbetween adjacent keys. In one embodiment, each guide arm 315 a and 315 bguides separate layers of a flex circuit. Opening 313 allows contact tobe made with the flex circuit. Hooks 316 a and 316 b secure a butterflylinkage (not shown) that is coupled to and supports a key top.

[0120]FIG. 32 shows an example of a method of using a collapsiblekeyboard in accordance with the teachings of the present invention. Instep 401, a first housing and a second housing are secured by a user'shands. Both housings are coupled to a collapsible support that supportsa number of keys. In step 402, the housings are pulled apart linearlysuch that the keys are exposed and the keyboard is expanded. In step403, the expansion of the keyboard is sensed (e.g. by a limit switch).

[0121]FIG. 33 shows another example of a method of using a collapsiblekeyboard in accordance with the teachings of the present invention. Instep 411, a first housing and a second housing are secured by a user'shands. Both housings are coupled to a collapsible support that supportsa number of keys. In step 412, the housings are pulled apart linearlysuch that the keys are exposed and the keyboard is expanded. In step413, the housings are pushed together such that substantially all of thekeys are covered and the keyboard is collapsed. In step 414, thehousings are latched together when the keyboard is collapsed.

[0122]FIG. 34 shows yet another example of a method of using acollapsible keyboard in accordance with the teachings of the presentinvention. In step 421, a first housing and a second housing aresecured, where both housings are coupled to a collapsible support thatsupports a number of keys. In step 422, the housings are pulled apartlinearly such that the keys are exposed and the keyboard is expanded. Instep 423, power is automatically provided to a keyboard circuit when thekeyboard is expanded.

[0123] Keyboard assemblies such as keyboard assembly 10, which isdescribed above, normally require some associated electrical circuitryto detect the actuation (e.g. pressing) of the various keys and thegeneration of appropriate signals which indicate the identity of theactuated key. Typically, each key has an associated electrical switchwhich produces an electrical change of state (e.g. electrically open toelectrically closed) when the associated key top is depressed.

[0124] In one embodiment of the keyboard assembly of the invention, eachkey base 11 b includes electrical elements 39, 40, 41, and 42 andresistor 503 and diode 504 as shown in FIG. 35. FIG. 35 illustrates anelectrical configuration of four keys of keyboard assembly 10.Conductive paths (e.g. conductive strips) or electrodes 39 and 42 bendat right angles over the face of key shoulders 43 on each key base 11 band electrically contact row linkages 4. On each key base 11 b,electrode 39 is coupled to one terminal of resistor 503, and electrode40 is coupled to the other terminal of resistor 503. On each key base 11b, electrode 40 is disposed physically near, but electrically isolatedfrom, electrode 41. Electrodes 40 and 41 are electrically coupled (e.g.“shorted”) when the key top is pressed toward the key base; typically,when the key top is pressed, an electrode coupled to the key top shortselectrodes 40 and 41, thereby closing the switch between electrodes 40and 41. Electrode 41 on each key base 11 b is coupled to one terminal ofdiode 504, and the other terminal of diode 504 is coupled to electrode42. Linkages 4 are made of a conductive material such as, for example,steel, aluminum, or plastic which is conductive or which includes anelectrically conductive material. Each row of linkages 4 acts as asingle wire electrical bus 44. Each bus 44 is connected to a keyboardcontroller (not shown in FIG. 24) which could be located in one side ofthe keyboard assembly housing. A cursor control device (such as atrackpad) and battery could be located in this same side of the housingor the other housing side. In another embodiment, a data transfer portis electrically connected to each bus 44 through the keyboard controlleror any other appropriate interface for communicating with a computersystem. The data transfer port may be a universal serial bus (USB) portor a “Firewire” port such as a port which substantially complies withIEEE Standard 1394.

[0125] In yet another embodiment, key bases 11 b and row spacing sleeves32 (see FIGS. 13 and 35) are made of a non-conductive material, such as,for example, plastic. Other materials (e.g. rod 31) in the keyboardassembly 10 which may serve as an electrical path from one row oflinkages 4 to another row of linkages 4 is also made from non-conductivematerials so that these rows remain electrically isolated. Hence, eachrow is electrically isolated from its adjacent row, although they sharea common framework of conductive linkages.

[0126]FIG. 36 shows a schematic diagram of one example of a typical keyencoder circuit 500 for a key. In the embodiment described herein, eachkey assembly, having a key top 11 a and a key base 11 b, contains a keyencoder circuit consisting of a key switch 502, a resistor 503, a diode504, and two terminals 501 and 505. In one embodiment, key switch 502(formed by electrodes 40, 41 and conductive face 45) is normally openand is closed when key top 11 a is pressed downward toward key base 11b.Diode 504 determines the polarity of the key circuit. Resistor 503determines the resistive load of the particular key 3 when switch 502 isclosed and diode 504 is biased with the current flow. Terminal 501 iscoupled to one bus 44 and terminal 502 is coupled to another bus 44.

[0127]FIG. 37 illustrates a row of 10 keys. Although FIG. 37 shows 10keys in the row, it is to be appreciated that the number of keys can bemore or less than this amount. In this embodiment, each key assembly hasone terminal connected to bus 520 (which may be a row of scissorslinkages) and the other terminal connected to bus 521 (which may be anadjacent row of scissors linkages). Keys in the row are arranged in twopolarity groups with half of the keys, e.g., 510, 511, 512, 513, and514, in one polarity and the remaining keys, 515, 516, 517, 518, and519, in the opposite polarity. Each key in a polarity group has adifferent resistive load and the resistor values differ exponentiallyfrom key to key. The keys are polarized by the diodes to allow the rowof keys to be divided into two sections to keep the ratio of the highestand lowest resistor values within a reasonable range, particularly whenthere are a large number of keys coupled between adjacent busses 44.

[0128]FIG. 38 shows a schematic block diagram of a partial row of keysof a keyboard assembly in accordance with the invention. Key assemblies580 and 590 are coupled in parallel between conductive pathways or buses575 and 576. Key assembly 580 includes a switch 581 coupled to atransponder 582, which receives power via wire 583. Key assembly 590includes a switch 591 coupled to a transponder 592, which receives powervia wire 593. Each transponder 582 and 592 is identified by a uniqueaddress. In one embodiment, a keyboard controller sends addresses downthe row of keys through bus 575. For each key that is pressed, therebyclosing the associated switch, the transponder coupled to that switchrecognizes its address and responds through bus 576. In one embodiment,transponders 582 and 592 are ASIC (Application Specific IntegratedCircuit) transponders. In one example, each transponder may transmit aunique, identifiable signal which is decoded by a keyboard interfacewhich is coupled to buses 575 and 576.

[0129]FIG. 39 shows a keyboard assembly consisting of an array of keys640, a keyboard interface 600, and a microcontroller 650. In thisexample, array of keys 640 is 6 rows of 15 keys. Each key in each row isconnected in parallel on a two-wire bus with adjacent rows of keyssharing a common bus. For example, the top row of keys (keys 640 a, 640b, . . . 640 o) are coupled in parallel on a two-wire bus formed byconductors 601 and 602. Conductor 601 may be a row of scissors linkages4 and conductor 602 may be an adjacent row of scissors linkages 4. Thus,each of conductors 601-607 may represent one of the busses 44 shown inFIG. 35. This arrangement has an advantage over traditionaltwo-dimensional key matrix arrays in that wire column buses are notrequired, thus decreasing the number of connections to keyboardinterface 600. This is particularly advantageous when the keyboard iscollapsible because wires in a collapsing structure may interfere withthe mechanics of collapsing, and the wires may also deteriorate overtime due to repeated expanding and collapsing of the keyboard.

[0130]FIG. 40 illustrates a keyboard interface 600 between array of keys640 and microcontroller 650. In this embodiment, analog multiplexers 608and 609 are used to enable one selected row of keys, in one polarity, atone time. Row address inputs 621, 622, and 623 of multiplexer 608determine which keyboard bus is connected to positive current sensesignal 610. Row address inputs 624, 625, and 626 of multiplexer 609determine which keyboard bus is connected to ground. Resistor 614 and618 create a voltage divider to generate a reference voltage signal 619for analog-to-digital converter 611 and operational amplifier 616.Operational amplifier 616 outputs a voltage that is relative to theamount of current drawn at positive sense signal 610. Analog to digitalconverter 611 is used to digitize the amount of current drawn by thebus, by measuring the output voltage of operational amplifier 616, andmakes a resulting digital value available to microcontroller 650 via bus612. Signal 613 is provided by microcontroller 650 and is used to starta new analog-to-digital conversion when microcontroller 650 needs tomeasure the bus current.

[0131] In the embodiment of FIG. 40, in operation, microcontroller 650scans the keyboard assembly, one row at a time, by sequentiallyaddressing each row of keys using row address signals 621, 622, and 623and 624, 625, and 626. The row addresses for multiplexers 608 and 609differ by one, in order to connect keyboard buses in adjacent pairs(e.g., 601 and 602, 602 and 603, etc.). Keyboard buses 602, 603, 604,605, and 606 are each shared by two rows of keys, decreasing the numberof connections to the keyboard assembly. Each row is addressed twice,once in each polarity.

[0132]FIG. 41 shows an example of keyboard 640 with three rows of eightkeys each. Keyboard array 640 is coupled to keyboard interface 600 whichis coupled to microcontroller 650 which is coupled to host computer 653or another host device (e.g. a cellular phone, information appliance,personal digital assistant, etc.). On power-up initialization,microcontroller 650 sets all row addresses 621, 622, 623, 624, 625, and626 to a low state. Microcontroller 650 begins scanning the first row ofkeys by setting row address signals 621, 622, and 623 to a binary valueof one. This connects bus 601 to current source 610 and the input ofanalog-to-digital converter 611. Next, row address signals 624, 625, and626 are set to a binary value of two, connecting bus 602 to ground. Atthis point, if any keys 531, 532, 533, or 534 are pressed, theindividual key's diode will be forward biased, allowing current to flowthrough the key's resistor. At this same time, keys 535, 536, 537, and538 have no effect on the bus since their diodes are reverse biased.Since each of the keys, 531, 532, 533, and 534 have a different resistorvalue, microcontroller 650 can determine which keys are pressed byanalyzing the current flow as measured by the voltage drop acrossresistor 614. Microcontroller 650 then analyzes keys 535, 536, 537, and538 by setting row address signals 621, 622, and 623 to a binary valueof two and row address signals 624, 625, and 626 to a binary value ofone. This reverses the polarity by connecting bus 602 to current source610 and bus 601 to ground. In this state, keys 531, 532, 533, and 534have no effect and current flow through keys 535, 536, 537, and 538 canbe analyzed to determine which of the keys are pressed. This cyclecompletes scanning of the first row of keys and the remaining rows arescanned in a similar fashion. When microcontroller 650 finds a depressedkey, it uses a table look-up method to locate the scan code for the keyand sends the scan code to host computer 653 or other host device. Thisentire scanning process repeats indefinitely, causing the keyboard to becontinuously scanned.

[0133] Each key in a polarity, group has a unique resistor value and,when pressed, adds a specific resistive load to the bus. Any givencombination of pressed keys along a row generates a unique andidentifiable resistive load, allowing the keys pressed to be identifiedby the microcontroller 650. Therefore, the design allows accurate keyidentification even when multiple keys are pressed simultaneously alongthe same row.

[0134]FIG. 42A shows a key encoder 720 of another embodiment of a keyidentification system. Key encoder 720 has a timer 750 with twoterminals 751, 752. Timer 750 is coupled to a switch 753 and anelectrical identifier 754, which in one embodiment, is a resistor. Timer750 is a circuit with an output that is low when powered up and thenbecomes high after a predetermined time period, thereby reaching anactive state. Switch 753 is closed when a corresponding key (not shown)is pressed. When switch 753 is closed and the output of timer 750 ishigh, electrical identifier 754 adds an identifying load. In otherwords, even if switch 753 is closed, the identifying signal provided byelectrical identifier 754 does not become electrically visible until theoutput of timer 750 is high.

[0135]FIG. 42B shows a row of keys 761-765, each of which has a keyencoder similar to key encoder 720 but with different timers 750 a-750e. Each key 761-765 is coupled to buses 701, 702. Timers 750 a-750 e arepreset to unique time constants such that identifying loads are notadded at the same time. Although five keys are shown in a row, thepresent invention is not limited to any particular number of keys in arow.

[0136]FIG. 43 is a detailed illustration of a keyboard interface 700used to couple an array of keys to a microcontroller and may be usedwith the key encoder shown in FIGS. 42A and 42B. Analog multiplexers708, 709 are used to enable one selected row of keys at a time. Rowaddress inputs 721-723 of multiplexer 708 determine which keyboard bus701-707 is connected to a current sense signal 715. Row address inputs724-726 of multiplexer 709 determine which keyboard bus is connected toground. Resistors 717, 718 create a voltage divider to generate areference voltage signal 719 for an analog-to-digital (A/D) converter711 and an operational amplifier (op-amp) 716. Op-amp 716 outputs avoltage that is relative to the amount of current drawn at current sensesignal 715. AND converter 711 digitizes the amount of current drawn bythe bus connected to current sense signal 715 by measuring andconverting the output voltage of op-amp 716. The resulting digital valueis sent to the microcontroller by a bus 712. The microcontrollerprovides an A/D sample clock signal 713 when the microcontroller needsto measure the bus current again.

[0137]FIG. 44 shows one implementation of keyboard interface 700 with anarray of keys 740 coupled through buses 701-707 to keyboard interface700 which is coupled to a microcontroller 770 coupled to a host computer773. The keyboard system of FIG. 44 is shown using the key encoder 720of FIG. 42A for each of the keys. Array of keys 740 has six rows 741-746of fifteen keys. All keys in a row are connected in parallel on atwo-wire bus, with adjacent rows sharing a common bus. For example, rows741 and 742 share bus 702. By not requiring column buses, thearrangement of buses 701-707 decreases the number of connections tokeyboard interface 700 and prevents buses from crossing over oneanother. Microcontroller 770 scans array of keys 740, one row at a time,by sequentially addressing rows 741-746 using row address signals721-726. In one embodiment, the row addresses for multiplexers 708, 709differ by one such that adjacent buses are paired together (buses 701and 702 for row 741, buses 702 and 703 for row 742, etc.).

[0138] To scan row 741, microcontroller 770 sets row address signals721-723 to the binary equivalent of 1 and row address signals 724-726 tothe binary equivalent of 2. This connects bus 701 to current sensesignal 715 and bus 702 to ground. Microcontroller 770 then determineswhich key(s) is/are being pressed according to the relative timing ofsignals, an example of which is shown in FIG. 45 using the signals forkeys 761-765.

[0139] Timer output signals 761 a-765 a for keys 761-765, respectively,go high sequentially at even time intervals. For example, timer outputsignal 761 a goes high at t2 and timer output signal 762 a goes high att 4. The relative bus current 710 drawn by bus 701 is shown with onlykeys 761, 763 and 765 pressed. A/D converter 711 samples relative buscurrent 710 when triggered by AND sample clock signal 713 at odd timeintervals. Starting with the sample taken at t 3, microcontroller 770compares each sample with the previous sample to determine if a key hasbeen pressed. In the example shown in FIG. 45, microcontroller 770 willdetermine that key 761 is pressed because a current increase occurredbetween the samples taken at t1 and t 3, and timer output signal 761 afor key 761 is the only signal that goes high at t2 when itscorresponding key is pressed. Microcontroller 770 will determine thatkey 762 is not pressed because a current increase did not occur betweenthe samples taken at t3 and t 5, and timer output signal 762 a for key762 goes high only at t4 when key 762 is pressed. Microcontroller 770checks each key in a row in a similar manner until all keys in a rowhave been checked. Although the timer output signals for five keys areshown in FIG. 45, the present invention is not limited to any particularnumber of keys.

[0140] In another embodiment of the invention, microcontroller 770verifies a scan by scanning a row a second time and comparing theresults with the first scan. If the rescan does not match the firstscan, the row is rescanned until two consecutive scans match. Once twoconsecutive scans match, the determination of pressed keys proceeds asdescribed above. If microcontroller 770 finds any pressed keys, it usesa table look-up method to find the scan code(s) for the key(s) and sendsthe scan code(s) to a host computer 773 via bus 772. All of rows 741-746are scanned similarly, row by row. The scanning process repeatsindefinitely, causing the keyboard to be scanned continuously.

[0141]FIG. 46 shows a linear matrix coupled to a row 800 of keysaccording to another embodiment of a key identification system inaccordance with the invention. Row 800 is separated electrically intofour sections 801 a-804 a by the connections of the keys with sectionpathways 801-804. Section 801 a consists of keys 801 b-801 e, which arecoupled to section pathway 801 (which may be considered to be anelectrical row in an electrical matrix). Section 802 a consists of keys802 b-802 e, which are coupled to section pathway 802 (which may beconsidered to be another electrical row in the electrical matrix).Section 803 a consists of keys 803 b-803 e, which are coupled to sectionpathway 803. Section 804 a consists of keys 804 b-804 e, which arecoupled to section pathway 804. Thus, each section has its ownelectrical pathway and effectively each section is an electrical matrixof key switches having at least one electrical row and severalelectrical columns. Each section may be regarded as an electricalsection of an electrical matrix. Each key in each section is alsocoupled to a key pathway, which is shared by corresponding keys in eachsection. For example, keys 801 b, 802 b, 803 b, 804 b are coupled to keypathway 805 (which may be considered a column) and keys 801 c, 802 c,803 c, 804 c are coupled to key pathway 806 (which may be consideredanother column). Thus, row 800 of keys appears electrically as if itwere arranged in a 4×4 matrix, but the matrix is confined to row 800which is a mechanical row of keys (e.g. row VI of FIG. 1), therebyallowing row 800 to be independent of and electrically isolated fromother rows. While FIG. 46 suggests that the keys are mechanically andphysically adjacent to each other along a row, it will be appreciatedthat the electrical sections along a row may include, in any oneelectrical section, distantly spaced, non-contiguous keys along the row(or another row in the case where the row [section] lines extend to theanother row). This is accomplished by wiring up the switches in eachnon-contiguous key to the desired row line. The linear matrix defined bysection pathways 801-804 and key pathways 805-808 allows each key to bechecked individually through the appropriate section and key pathways.In one embodiment, the section pathway for each section is provided byan electrode to which each key in the section is coupled, and the keypathways for each section are provided by a group of electrodes, eachone of which is coupled to a key in the section. It should be noted thatthe sections can consist of any number of keys and are not limited tohaving equal numbers of keys. In an alternative embodiment, a row ofkeys could be separated into left and right electrical sections and eachreceives a wiring bus from its respective side.

[0142] In one exemplary embodiment of the invention, the sectionpathways and the key pathways are, at least in part, provided byflexible conductors which may be flexible wires on a flexible plasticsubstrate. These flexible conductors may be positioned on the key basesand under the key tops as shown in FIGS. 30A through 30C. The flexibleconductors allow the keyboard to be expanded and collapsed as shown inFIGS. 30A through 30C without requiring, on one row, as many conductorsas is normally required for a conventional keyboard electrical matrix(e.g. for a mechanical row of 16 keys, a conventional keyboardelectrical matrix requires 17 conductors [16 column wires and 1 rowwire], while the keyboard electrical matrix requires only 8 conductors).Furthermore, flexible conductors electrically arranged in a matrix as inFIG. 46 allow a row to be isolated electrically from other rows so thatno “column” wires are required to interconnect between the rows. Thatis, all the wires for a row can run along the row and no wires (e.g. nocolumn wires) need to run between rows in the collapsible portion of thekeyboard assembly, thereby making mechanical expansion and contractioneasier to implement. This isolation between rows requires a separate setof column conductors for each row but this extra set is balanced by theimproved mechanical handling of the collapsible keyboard.

[0143] The flexible conductors may consist of one or more layers offlexible material. For example, a single-layer conductor may havecircuits applied to one face of a flexible material. It may have apattern of open contacts under each key. When a key is pressed, anelectrically conductive puck attached to the key shorts the contacts,which completes a circuit.

[0144] In the preferred embodiment, a two-layer membrane is used. Thesemembranes each have circuits of silk-screened silver applied to theiropposing faces. The circuits are insulated by a coating such as lacquerexcept in the areas under each key, where they are separated by a raiseddeposit of material (for example, a pattern of non-conductive ink). Whena key is pressed, the two layers meet and their contacts join tocomplete a circuit.

[0145] A three-layer membrane has an insulating layer of non-conductivematerial between two layers, which have circuits of silk-screened silverapplied to their opposing faces. The insulating layer has a hole undereach key, such that when a key is pressed, the two outer layers meetthrough the hole and their contacts join to complete a circuit.

[0146]FIG. 47 is a block diagram of a keyboard array 150 with six rows103-108 of keys, where rows 103-108 are configured similarly to row 800of coupled to a keyboard interface 100 which is coupled to amicrocontroller 101 which is coupled to a host computer 102 or otherprocessing system. In one embodiment, keyboard interface 100 allowsmicrocontroller 101 to access keyboard array 150 as if it were an 8×12(key×section) matrix by logically connecting common section and keysignals from rows 103-108. For example, rows 103-105 have common keysignals 109 a-109 c, and rows 103 and 106 have common section signals111 a and 111 b. In one embodiment, section signals 111 a-113 a and 111b-113 b are each associated with four sections in a row, and key signals109 a-109 c and 110 a-110 c are each associated with the four keys ineach of the four sections. For example, section signal 111 a isassociated with section S1-S4, and key signal 109 a is associated withkeys K1-K4. All key signals and section signals communicate withmicrocontroller 101 via keyboard interface 100 and interface signals 120and 130.

[0147] To begin scanning keyboard array 150, microcontroller 101 entersa mode of operation in which it activates all sections (S1-S12) throughinterface signal 130 to keyboard interface 100 and detects any responsethrough interface signal 120 from keyboard interface 100 to determine ifany keys are pressed. Microcontroller 101 remains in this mode andrepeats the process periodically until it detects a pressed key.

[0148] Once a pressed key is detected, microcontroller 101 entersanother mode of operation in which it scans keyboard array 150, onesection at a time, by activating individually each section (S1-S12)through interface signal 130 to keyboard interface 100 and detecting anyresponse through interface signal 120 from keyboard interface 100. In analternative embodiment, one section in each of several rows may beactivated concurrently to separately determine whether, in theappropriate section of each row, a key was pressed. Thus, severalsections, each in an electrically separate row, may be activatedconcurrently. For each section, a response signal will be supplied byone or more keys depending on which keys in that section are pressed.Typically the sections are scanned in some order, such as a sequentialorder. If microcontroller 101 detects any response signal(s), it entersyet another mode of operation in which it uses a table look-up method tofind the scan code(s) for the pressed key(s) and sends the scan code(s)to host computer 102. The entire scanning process repeats indefinitely,causing keyboard array 150 to be scanned continuously.

[0149] FIGS. 48A-48C show one embodiment of the key identificationsystem shown in FIG. 46. Flexible lower layer 910 is disposed over a keybase 900 such that contact region 915 of lower layer 910 rests on keybase 900. Flexible upper layer 920 is disposed over lower layer 910 suchthat contact region 925 of upper layer 920 is located directly abovecontact region 915 of lower layer 910. In one embodiment, conductivetraces 911-914 are section pathways and conductive traces 921-924 arekey pathways, where the section and key pathways are similar to thosedescribed with reference to FIG. 46. Contact regions 915 and 925 aredesigned to selectively bring two conductors (one from traces 921-924and one from traces 911-914) into electrical contact when the key top ispressed. In one embodiment, both ends of both lower layer 910 and upperlayer 920 (at the end of each row) are connectable to a cursor controldevice and to keyboard interface circuitry thereby allowing the cursorcontrol device to be positioned on either side of the keyboard; this isshown in FIG. 48E and is described further below. It should be notedthat FIGS. 48A and 48B show lower layer 910 and upper layer 920individually, respectively, to depict more clearly the features of lowerlayer 910 and upper layer 920.

[0150] In another embodiment of the invention, a keyboard assembly hasmultiple rows of keys where each row is coupled to a differentconductive bus. Each row is also coupled to a different group of columnelectrodes, and each key in the row is coupled to one row electrode. Inother words, each row has its own row conductor, and each key in eachrow has its own column conductor. FIG. 48D shows an example of such asystem where a mechanical row 944 of keys has a row conductor 940 andseveral column conductors 941, and another mechanical row 945 of keyshas an electrically separate row conductor 942 and several columnconductors 943 (which may be electrically separate from column conductor941).

[0151]FIG. 49 shows an example of a method for detecting key actuationin accordance with the teachings of the present invention. In step 950,a row of keys is electrically separated into different sections (anexample of this is shown in FIG. 46). In step 951, the differentsections are scanned sequentially to detect a key actuation signal thatcorresponds to a pressed key. In step 952, a scan code corresponding tothe key actuation signal is sent to a host computer.

[0152]FIG. 50 shows another example of a method for detecting keyactuation in accordance with the teachings of the present invention.This method is similar to the manner in which the keyboard array 150 ofFIG. 47 is scanned. In step 960, a row of keys is electrically separatedinto different sections (for example, as in FIG. 46). In step 961, thesections are scanned concurrently to detect a key actuation signal. Instep 962, if a key actuation signal is detected, then step 963 isperformed. If a key actuation signal is not detected, then the step 961is repeated. In step 963, the sections are scanned sequentially tofurther detect the key actuation signal. In step 964, a scan codecorresponding to the key actuation signal is sent to a host computer.

[0153]FIG. 51 shows yet another example of a method for detecting keyactuation in accordance with the teachings of the present invention. Instep 970, a row of keys is electrically isolated (for example, as inFIG. 46). In step 971, timers that are coupled to each key in the roware activated. In step 972, a first signal from the row of keys issampled at a first time. Then in step 973, a second signal from the rowof keys is sampled at a later time. In step 974, the sample of thesecond signal is compared with the sample of the first signal toidentify any pressed keys. In step 975, scan code(s) corresponding tothe pressed key(s) are located. In step 976, the scan code(s) is/aresent to a host computer. In another example, each key produces anidentifying signal when its timer is in an active state and the key ispressed. In another example, the timers reach an active state atdifferent times.

[0154]FIG. 52 shows still another example of a method for detecting keyactuation in accordance with the teachings of the present invention. Instep 980, a row of keys is electrically isolated. In step 981, timerscoupled to each key in the row are activated. In step 982, a firstsignal from the row of keys is sampled at a first time. In step 983, asecond signal from the row of keys is sampled at a later time. In step984, the second signal is resampled. In step 985, if the resample of thesecond signal substantially matches the first sample of the secondsignal, then step 986 is performed. If the resample and the first sampledo not substantially match, then step 984 is performed again. In step986, the resample of the second signal is compared with the sample ofthe first signal to identify any pressed keys.

[0155] In one embodiment of the invention, the surface of one of housingsides 1 and 2 may include a cursor control device such as a smalltrackball, a touch-sensitive trackpad, a joystick, a pressure-sensitivepointing device (e.g. IBM's TrackPoint III which is used on IBM'sThinkPad laptop computers), or other cursor control (e.g. pointing)devices. In addition, small buttons may be included on the surface ofthe housing; these small buttons may perform the same functions as thebuttons (or button) on a mouse which is often used with a computer. Inanother embodiment, the cursor control device is selectivelypositionable on either one of housing sides 1 and 2.

[0156]FIG. 48B shows one example of an embodiment of the invention inwhich a cursor control device, such as a track pad, is selectivelypositionable on either side of a keyboard, such as a collapsiblekeyboard assembly according to the present invention. In this way, auser of such a keyboard may position the cursor control device on eitherthe left side or the right side of the collapsible keyboard depending onthe user's preference. In another embodiment, a cursor control devicecan be placed between the keys. For example, a pointing stick, such asIBM's TrackPoint (found on IBM's ThinkPad laptop computers) can beplaced between the G, H, & B keys. The flexible conductors associatedwith adjacent rows of keys can conduct the electrical signals from thepointing stick to the keyboard controller. In addition, small buttonswitches may be included on the surface of the first row of scissorslinkages; these small switches may perform the same functions as theswitches (or switch) on a mouse which is often used with a computer.

[0157] In the example shown in FIG. 48E, a keyboard is assumed tocommunicate with a host computer or other host processing systems suchas a personal digital assistant. However, the keyboard may include acomplete computer system as shown in FIG. 53 and also provide thecapability of selectively positioning the cursor control device oneither side of the keyboard. The keyboard 1001 shown in FIG. 48Eincludes a key assembly 1004 having end plates 1005 and 1006. Two rowsof keys are shown, but it will be understood that fewer or more rows ofkeys may exist. Each row of keys includes section lines and key lines,such as section lines 1007 or 1009 and key lines 1008 or 1010. Thekeyboard 1001 may be implemented as a collapsible keyboard by usingscissors linkages or by allowing the keyboard to fold (e.g. fold inhalves or thirds at hinged joints which separate foldable sections ofthe keyboard). It will be understood that section lines 1007 are similarto section lines 801-804 of FIG. 46 and that key lines are similar tothe key lines 805-808 of FIG. 46. Each of these groups of lines includesa connector which may be mounted to the end plates and which allows thelines to couple to module 1003 which includes the cursor control device1115. These connectors, shown as connectors 1111 a, 1111 b, 1111 c, and1111 d are located on either side of the assembly of the keys 1004,thereby allowing the module 1003 to be coupled to either side of theassembly of keys. As shown in FIG. 48E, the module 1003 is coupled tothe left side of the assembly while the module 1002 is coupled to theright side. This may be reversed by disconnecting module 1002 from theright side and disconnecting the module 1003 from the connectors on theleft side and coupling it through module 1003's connectors 1111 e, 1111f, 1111 g, and 1111 h to the corresponding connectors 1111 a, 1111 b,1111 c, and 1111 d on the right side of the key assembly. The module1003 includes a cursor control device 1115 which is coupled to akeyboard interface and I/O interface 1116 which also provides a cursorcontrol device controller. This component 1116 provides conventionalcursor control interface as well as I/O (input/output) interfacefunctionality and keyboard interface functionality. For example,component 1116 may provide the functionality of the keyboard interface100 and the microcontroller 101 shown in FIG. 47 in addition toproviding the functionality of controlling the cursor control device. Inaddition, component 1116 provides the I/O interface to a host computerthrough the connection 1117. In an alternative embodiment, theconnection may be a port located in the middle of the rear of thecollapsible keyboard; this port is mechanically like another key exceptthat space around the port may exist because there are no adjoining keysnext to the port and thus, a keyboard may still collapse withoutimpinging on the port. Component 1116 is coupled to the connection portson the left side of module 1003 by bus 1114 b, and it is coupled to theconnection ports on the right side of the module 1003 by the bus 1114 a.It will be appreciated that module 1002 may be empty or may containelectronic components which are appropriate for the device. For example,the module 1002 may include a small liquid crystal display or a storagedevice or both, and these components and module 1002 may be coupledthrough a flexible conductor bus to module 1003. In one embodiment ofthe invention, a complete personal digital assistant may be assembledinto the collapsible keyboard by using the space within the modules 1003and 1002. An example of such a system will now be described inconjunction with FIG. 53.

[0158]FIG. 53 shows an example of a collapsible keyboard system 1050with a collapsible keyboard assembly 1051 and a processor module 1052.The processor module may be housed in the housing 1 or the housing 2shown in FIG. 1 or may be housed in both housings with flexibleconductors providing signals between the two housings as necessary.Module 1052 includes a keyboard controller 1053, memory 1054, a systembus 1055, a microprocessor 1056, and an input/output controller 1057.The module also includes two input/output ports 1058 and 1059. Thekeyboard controller 1053, the memory 1054, the microprocessor 1056, andthe I/O controller 1057 are interconnected by the system bus 1055. Thekeyboard controller 1053 may be a controller which provides thefunctionality of the keyboard interface 100 and the microcontroller 101of FIG. 47 or it may be other types of keyboard interfaces and/ormicrocontrollers which can provide scan codes to the system bus 1055 foruse by the microprocessor 1056 and/or storage into memory 1054. Thememory 1054 may be DRAM or flash memory or other types of storagedevices. Furthermore it may include mass storage such as a magnetic harddisk or other types of mass storage to the extent it is possible toinclude such memory in a small space. The microprocessor 1056 may be anyconventional microprocessor or microcontroller although it is preferablethat it is a general purpose microprocessor which is controlled undercontrol of computer program instructions which are stored in memory1054. Alternatively, the microprocessor 1056 may be a microcontrollerwhich, on a single semiconductor substrate, includes the memory whichstores the computer program which is executed by the microcontroller.The I/O controller 1057 may be a conventional input/output controllerwhich can perform direct memory access to the memory 1054 and which alsocan communicate data to and from the microprocessor 1056. The I/Ocontroller 1057 provides input and output control for the two ports 1058and 1059. In one example of the present invention, the input/output port1058 may be a universal serial bus (USB) port or an infrared port or aserial port (such as an RS-232 port) or a conventional parallel port.The other input/output port may be a Firewire port, which may beconsidered to be a port which substantially complies with the IEEEstandard known as 1394. This Firewire port may provide output to adisplay device such as a miniature head-mounted display which canproject to a viewer's eye an image of a display. Alternatively, thisport 1059 may be coupled to a standard computer monitor rather than aminiature head-mounted display. It will be appreciated that in oneembodiment, no display is included into the collapsible keyboard system1050, but rather, data for the display is separately provided throughthe port 1059 as described herein. Another example of a port may be aport which complies with the PCMCIA standard, such as the conventionalPC Card or PC Card bus ports found on modern laptop computers.

[0159] In one example of the present invention, the input/output portmay be a universal serial bus (USB) port or a serial port (such as anRS-232 port) or a “PS/2” port or an infrared port or a radio frequencyport or a parallel port or a Firewire port, which may be considered tobe a port which substantially complies with the IEEE standard known as1394 or several ports providing a combination of these ports.

[0160] In another example of the present invention, a “docking station”may be provided to accommodate various devices such as Palm Computing's“PalmPilot.” In this example, the docking station consists of amechanical/electrical connector which allows the PalmPilot to mount tothe rear of the keyboard and communicate with the keyboard through thePalmPilot's serial interface. In this manner, the user can comfortablyenter data with the keyboard while viewing the PalmPilot's display. Thekeyboard may also include an additional port for a wired or wirelessmodem. With this configuration, the keyboard and PalmPilot could be usedfor sending and receiving e-mail or various Internet applications.Wireless phones and other information appliances may be docked in asimilar manner. Additional flexible conductors associated with the lastrows of keys can conduct the electrical signals from the docked deviceto the keyboard controller.

[0161] An alternative embodiment of a keyboard assembly of the presentinvention uses alphanumeric keys which use only two different keyassemblies for a collapsible keyboard. In one embodiment of the presentinvention, the scissors linkage structure has pivot points which aredesigned to reach a pitch of approximately 19 millimeters from eachother when the structure is fully expanded. The key switch assembliesattach to these pivot points, and common pivot points are shared betweenadjacent rows on the collapsible keyboard. However, standard keyboardlayouts typically require that the keys in one row be offset from keysin the next row by a fixed dimension. In one example the offset betweenthese rows is approximately one-quarter of a key width.

[0162] It is possible to satisfy this offset between the rows whileusing only two key assemblies which are designated as key assembly A andkey assembly B. The relative center key position difference between keyA and key B is one-quarter of a key width. Therefore, if key Aassemblies were placed in one row and key B assemblies were placed in anadjacent row, the two rows would be offset each other by one-quarter ofa key width. Since in one design the collapsing keyboard requires somerows to fold left and others to fold right, this is taken into accountwhen positioning the key center of key A and key B relative to the pivotpoint of the scissors linkage structure. The result of this is that thekey A center is ⅜ of a key width from the pivot point and key B is ⅛ ofa key width from a pivot point. The combination of ¼ key offset and ⅛ to⅜ pivot offsets creates additional combinations of offsets. Further,increments of ¼ key offsets can be combined to give ½ key offsets invarious folding directions.

[0163] The foregoing description provides examples of differentembodiments of the invention. Other implementations will be appreciatedby those skilled in the art. For example, rather than using scissorslinkages, a support element for the keys may be a telescoping set ofelements which slide along each other to expand and collapse. Each keymay be pivotally coupled to two such elements and rotate upon expandingor collapsing. The keys in one embodiment may use thin membrane switcheswithout butterfly linkages or springs, and thus the key top and key basemay be used to cause two conductive to come into electrical contact.Further, these membrane switches may fold rather than pivot. A membraneswitch may be coupled to a telescoping or scissors linkage supportmember at two points and may fold as a cloth seat of a director's chairfolds when this chair is collapsed. A flexible conductor assembly may bedisposed on a surface of the membrane switch and may fold with themembrane switch. In certain embodiments, a keyboard assembly of theinvention may include certain ergonomic features, such as a splitkeyboard or a palmrest which may be attached and detached from thekeyboard assembly.

[0164] In other embodiments of the invention, the relative functions ofthe rows and columns may be reversed. For example, the columns, ratherthan the rows, may fold/collapse to achieve a keyboard which candecrease in depth but not width. This may be implemented by providingcolumns of scissors linkages rather than rows of scissors linkages. In arelated way, the columns of keys may be electrically isolated in asimilar fashion as the rows are electrically isolated (as in, forexample, FIGS. 46 and 48D), and each column may include severalelectrical sections of an electrical matrix which is separate anddistinct from another electrical matrix formed in another column. Othermodifications and implementations will be appreciated from thisdisclosure.

[0165] In the preceding detailed description, the invention is describedwith reference to specific embodiments thereof. It will, however, beevident that various modifications and changes may be made theretowithout departing from the broader spirit and scope of the invention asset forth in the claims. The specification and drawings are,accordingly, to be regarded in an illustrative rather than a restrictivesense.

What is claimed is:
 1. A keyboard assembly for entering data, saidkeyboard assembly comprising: a first collapsible conductive member; asecond collapsible conductive member; and a plurality of keyselectrically coupled in parallel between said first collapsibleconductive member and said second collapsible conductive member, saidfirst collapsible conductive member providing at least one signal whichidentifies an actuated key of said plurality of keys.
 2. A keyboardassembly as in claim 1 wherein said plurality of keys each include aswitch which is coupled in parallel between said first collapsibleconductive member and said second collapsible conductive member.
 3. Akeyboard assembly as in claim 2 wherein each key of said plurality ofkeys comprises a first pivot which couples said each key to said firstcollapsible conductive member and a second pivot which couples said eachkey to said second collapsible conductive member.
 4. A keyboard assemblyas in claim 3 wherein said switch is electrically coupled to said firstcollapsible conductive member at said first pivot and said switch iselectrically coupled to said second collapsible conductive member atsaid second pivot.
 5. A keyboard assembly as in claim 1 furthercomprising a third collapsible conductive member and wherein saidplurality of keys comprises a first row of keys and an another pluralityof keys which comprises a second row of keys, said second row of keysbeing electrically coupled in parallel between said second collapsibleconductive member and said third collapsible conductive member, whereinsaid first row of keys and said second row of keys are electricallysensed separately and sequentially.
 6. A keyboard assembly as in claim 5wherein said first row of keys and said second row of keys areelectrically isolated.
 7. A keyboard assembly as in claim 1 wherein saidfirst collapsible conductive member is a first row of scissors linkagesand said second collapsible conductive member is a second row ofscissors linkages.
 8. A keyboard assembly as in claim 1 whereinelectrical power is supplied to a circuit of said keyboard assemblyautomatically as said keyboard assembly is expanded.
 9. A keyboardassembly as in claim 2 wherein each of said keys comprises anidentifying electrical element which identifies said each key based upona state of said switch.
 10. A keyboard assembly as in claim 1 whereinsaid at least one signal is controlled by a timer coupled to saidactuated key.
 11. A keyboard assembly as in claim 1 further comprising adata transfer port electrically coupled to said first collapsibleconductive member for communicating with a computer system.
 12. Akeyboard assembly as in claim 11 wherein said data transfer portcomprises a USB port.
 13. A keyboard assembly as in claim 11 whereinsaid data transfer port comprises a port substantially complying with anIEEE 1394 standard.
 14. A keyboard assembly for entering data, saidkeyboard assembly comprising: a collapsible support element having aconductive path; and a plurality of keys mechanically coupled to saidcollapsible support element, each of said keys comprising an electricalelement which is electrically coupled to said conductive path.
 15. Akeyboard assembly as in claim 14, wherein said conductive path is anintegral part of said collapsible support element.
 16. A keyboardassembly as in claim 15, wherein said electrical element comprises aswitch.
 17. A keyboard assembly as in claim 16 wherein said collapsiblesupport element comprises a row of scissors linkages.
 18. A keyboardassembly as in claim 14 wherein each key of said plurality of keys isrotatably coupled to a pivot point on said collapsible support element.19. A keyboard assembly as in claim 17 wherein each key of saidplurality of keys is rotatably coupled to at least one scissors linkagesof a row of scissors linkages and wherein said collapsible supportelement comprises said row of scissors linkages.
 20. A keyboard assemblyas in claim 16 wherein each of said keys is supported by only saidcollapsible support element.
 21. A keyboard assembly as in claim 16further comprising a first housing and a second housing which arecoupled to said collapsible support element, said first housing and saidsecond housing substantially enclosing said plurality of keys when saidkeyboard assembly is substantially collapsed.
 22. A keyboard assembly asin claim 16 wherein each key of said plurality of keys comprises anelectrical identifier which is selectively coupled electrically to saidcollapsible support element by a state of said switch.
 23. A keyboardassembly as in claim 22 wherein said collapsible support elementcomprises a conductive material.
 24. A keyboard assembly for enteringdata, said keyboard assembly comprising: a first conductive member; afirst row of keys each having a first electrical element which iselectrically coupled to said first conductive member; and a second rowof keys each having a second electrical element which is electricallycoupled to said first conductive member.
 25. A keyboard assembly as inclaim 24 wherein said first row is adjacent to said second row.
 26. Akeyboard assembly as in claim 24 wherein said first conductive membercomprises a row of scissors linkages.
 27. A keyboard assembly as inclaim 24 wherein said first electrical element is a first switch andsaid second electrical element is a second switch.
 28. A keyboardassembly as in claim 27 wherein said first row of keys and said secondrow of keys are electrically sensed separately and sequentially.
 29. Akeyboard assembly as in claim 28 wherein said first row is adjacent tosaid second row.
 30. A keyboard assembly as in claim 27 wherein each keyof said first row of keys comprises an identifying electrical elementwhich identifies said each key determined by a state of said switch ofsaid each key.
 31. A keyboard assembly as in claim 24 wherein said firstrow of keys is electrically isolated from said second row of keys.
 32. Akeyboard assembly as in claim 24 further comprising a second conductivemember which is electrically coupled to said second row of keys.
 33. Akeyboard assembly as in claim 32 wherein said second row of keys iscoupled in parallel between said first conductive member and said secondconductive member.
 34. A keyboard assembly for entering data, saidkeyboard assembly comprising: a first conductive member; a secondconductive member; and a first plurality of keys electrically coupled tosaid first conductive member and to said second conductive member, eachof said keys comprising an electrical identifier and a switch whichprovides a signal through at least one of said first conductive memberand said second conductive member which identifies said each of saidkeys.
 35. A keyboard assembly as in claim 34 wherein said firstplurality of keys are electrically coupled in parallel between saidfirst conductive member which is flexible and said second conductivemember which is flexible.
 36. A keyboard assembly as in claim 34 whereinsaid first conductive member and said second conductive member aremechanically coupled to said first plurality of keys to support saidfirst plurality of keys.
 37. A keyboard assembly as in claim 34 whereinsaid each of said keys further comprises a biasing element coupled tosaid electrical identifier to electrically bias said electricalidentifier.
 38. A keyboard assembly as in claim 37 wherein said biasingelement comprises a diode. 37A. A keyboard assembly as in claim 36further comprising: a third conductive member; and a second plurality ofkeys electrically coupled to said third conductive member and saidsecond conductive member, each of said keys of said second plurality ofkeys comprising another electrical identifier and another switch whichprovide another signal through at least one of said second conductivemember and said third conductive member which identifies said each keyof said second plurality of keys. 38A. A keyboard assembly as in claim37A wherein said first plurality of keys form a first row of keys andsaid second plurality of keys form a second row of keys, and whereinsaid first row of keys and said second row of keys are electricallysensed separately and sequentially.
 39. A keyboard assembly as in claim36 further comprising: a third conductive member; a fourth conductivemember; and a second plurality of keys electrically coupled to saidthird and said fourth conductive members, each of said keys of saidsecond plurality of keys comprising another electrical identifier andanother switch which provide another signal through at least one of saidthird and said fourth conductive members.
 40. A keyboard assembly as inclaim 39 wherein said first plurality of keys form a first row of keysand said second plurality of keys form a second row of keys which isadjacent to said first row of keys.
 41. A keyboard assembly as in claim36 further comprising a housing which is coupled to said firstconductive member and said second conductive member, and wherein saidhousing is part of a portable computer.
 42. A keyboard assembly as inclaim 36 wherein said electrical identifier comprises a resistor.
 43. Akeyboard assembly as in claim 41 wherein said keyboard assembly is notcollapsible.
 44. A keyboard assembly for entering data, said keyboardassembly comprising: a first conductive member; a second conductivemember; and a first plurality of keys electrically each coupled inparallel between said first conductive member and said second conductivemember, an actuated key of said first plurality of keys causing a signalwhich identifies said actuated key to be conducted through at least oneof said first conductive member and said second conductive member.
 45. Akeyboard assembly as in claim 44 wherein each key of said firstplurality of keys comprises an electrical identifier which provides saidsignal.
 46. A keyboard assembly as in claim 45 wherein each key of saidfirst plurality of keys comprises an electrical switch coupled to saidelectrical identifier.
 47. A keyboard assembly as in claim 46 wherein anelectrical state of said electrical switch causes said signal to beconducted through said at least one of said first conductive member andsaid second conductive member.
 48. A keyboard assembly as in claim 47wherein said first conductive member and said second conductive memberare mechanically coupled to said first plurality of keys to support saidfirst plurality of keys.
 49. A keyboard assembly as in claim 48 furthercomprising: a third conductive member; and a second plurality of keyselectrically coupled to said third conductive member and said secondconductive member, each of said keys of said second plurality of keyscomprising another electrical identifier and another switch whichprovide another signal through at least one of said second conductivemember and said third conductive member which identifies said each keyof said second plurality of keys.
 50. A keyboard assembly as in claim 49wherein said first plurality of keys form a first row of keys and saidsecond plurality of keys form a second row of keys, and wherein saidfirst row of keys and said second row of keys are electrically sensedseparately and sequentially.
 51. A keyboard assembly as in claim 48further comprising: a third conductive member; a fourth conductivemember; and a second plurality of keys electrically coupled to saidthird and said fourth conductive members, each of said keys of saidsecond plurality of keys comprising another electrical identifier andanother switch which provide another signal through at least one of saidthird and said fourth conductive members.
 52. A keyboard assembly as inclaim 51 wherein said first plurality of keys form a first row of keysand said second plurality of keys form a second row of keys which isadjacent to said first row of keys.
 53. A keyboard assembly as in claim48 further comprising a housing which is coupled to said firstconductive member and said second conductive member, and wherein saidhousing is part of a portable computer and said keyboard assembly is notcollapsible.
 54. A keyboard assembly for entering data, said keyboardassembly comprising: a first row of keys disposed mechanically along atleast a first support member; a first section of an electrical matrixcoupled to a first portion of said first row of keys; and a secondsection of said electrical matrix coupled to a second portion of saidfirst row of keys.
 55. A keyboard assembly as in claim 54 wherein saidfirst section of an electrical matrix comprises a first electrodecoupled to each key of said first portion of said first row of keys anda first plurality of electrodes, each electrode of said first pluralityof electrodes coupled to one key of said first portion of said first rowof keys, and further wherein said second section of an electrical matrixcomprises a second electrode coupled to each key of said second portionof said first row of keys and a second plurality of electrodes, eachelectrode of said second plurality of electrodes coupled to one key ofsaid second portion of said first row of keys.
 56. A keyboard assemblyas in claim 54 wherein said first section and said second section ofsaid electrical matrix are provided by a first conductive layer and asecond conductive layer and wherein said electrical matrix comprises atleast two row conductors and at least two column conductors.
 57. Akeyboard assembly as in claim 56 wherein each key of said first row ofkeys comprises a key base and a key top, said first and secondconductive layers having portions disposed between said key base andsaid key top, said each key being configured to hold said first andsecond conductive layers against an edge of said key base.
 58. Akeyboard assembly as in claim 56 wherein each of said first and secondconductive layers has a first end and a second end, each of said firstand second ends being couplable to a cursor control device.
 59. Akeyboard assembly as in claim 56 wherein said first and secondconductive layers are flexible and wherein said first plurality ofelectrodes and said second plurality of electrodes are the same.
 60. Akeyboard assembly as in claim 54 further comprising: a second row ofkeys disposed mechanically along at least a second support member, saidsecond row of keys being electrically isolated from said first row ofkeys; a third section of another electrical matrix coupled to a firstportion of said second row of keys; and a fourth section of said anotherelectrical matrix coupled to a second portion of said second row ofkeys.
 61. A keyboard assembly as in claim 54 further comprising a signaldetector coupled to said first section of an electrical matrix and saidsecond section of said electrical matrix, said signal detector beingconfigured to scan sequentially said first section and said secondsection of said electrical matrix.
 62. A keyboard assembly for enteringdata, said keyboard assembly comprising: a conductive member; and a rowof keys electrically coupled to said conductive member, each key of saidrow of keys comprising a timer and a switch, said timer controlling asignal provided by said switch.
 63. A keyboard assembly as in claim 62further comprising an electrical identifier coupled to said timer andwherein said keys of said row of keys are mechanically coupled to saidconductive member.
 64. A keyboard assembly as in claim 63 wherein saidelectrical identifier comprises a resistor.
 65. A keyboard assembly asin claim 62 wherein said signal is provided according to an activationoutput of said timer.
 66. A method for detecting key actuation in akeyboard assembly, said method comprising: separating electrically a rowof keys into a plurality of sections; scanning said plurality ofsections to detect a key actuation signal corresponding to a pressed keyof said row of keys; and sending a scan code corresponding to said keyactuation signal to a digital processing system.
 67. A method as inclaim 66 further comprising scanning concurrently said plurality ofsections to detect said key actuation signal, wherein said step ofscanning concurrently is performed before said step of scanning.
 68. Amethod as in claim 67 wherein said scanning and sending a scan code areperformed only if said scanning concurrently results in the detection ofat least one key actuation signal.
 69. A method as in claim 67 whereinsaid scanning concurrently is performed until at least one key actuationsignal is detected.
 70. A method as in claim 66 wherein said pluralityof sections comprise an equal number of keys.
 71. A method for detectingkey actuation in a keyboard assembly, said method comprising: isolatingelectrically a row of keys; activating a plurality of timers, each timerof said plurality of timers being coupled to a key in said row of keys;sampling a first signal from said row of keys at a first time to providea sample of said first signal; and sampling a second signal from saidrow of keys at a second time to provide a sample of said second signal,said second time being later than said first time.
 72. A method as inclaim 71 further comprising comparing said sample of said second signalwith said sample of said first signal, thereby identifying a pressedkey.
 73. A method as in claim 72 further comprising: locating a scancode corresponding to said pressed key; and sending said scan code to adigital processing system.
 74. A method as in claim 72 furthercomprising: resampling said second signal to provide a resample of saidsecond signal until said resample of said second signal substantiallymatches said sample of said second signal; and using said substantiallymatching resample in said comparing with said sample of said firstsignal.
 75. A method as in claim 71 wherein each key in said row of keysproduces an identifying signal when said each timer is in an activestate and said each key is pressed.
 76. A method as in claim 71 whereinat least two timers of said plurality of timers reach an active state atdifferent times.
 77. A keyboard assembly for entering data, saidkeyboard assembly comprising: a first row of keys coupled to a firstconductive member, each key of said first row of keys being coupled toan electrode of a first group of electrodes; and a second row of keyscoupled to a second conductive member, each key of said second row ofkeys being coupled to an electrode of a second group of electrodes, saidsecond row of keys being electrically isolated from said first row ofkeys.
 78. A keyboard assembly as in claim 77 wherein said keyboardassembly is capable of existing in an expanded state and a compressedstate.
 79. A keyboard assembly for entering data, said keyboard assemblycomprising: a conductive pathway; and a row of keys coupled to saidconductive pathway, each key of said row of keys comprising a switchcoupled to an active electrical identifier, said active electricalidentifier of said each key providing a unique identifying signal.
 80. Akeyboard assembly as in claim 79 wherein said active electricalidentifier comprises an ASIC transponder.